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On my laptop I run Debian Testing with no Desktop Environment.

I manage the Wifi connections by adding entries to /etc/network/interfaces and then running /etc/init.d/networking restart.

dmesg says:

[299290.544631] wlp58s0: deauthenticating from 48:3c:0c:61:4f:14 by local choice (Reason: 3=DEAUTH_LEAVING)
[299291.069299] IPv6: ADDRCONF(NETDEV_UP): wlp58s0: link is not ready
[299294.563615] wlp58s0: authenticate with 18:a6:f7:32:37:ab
[299294.571331] wlp58s0: send auth to 18:a6:f7:32:37:ab (try 1/3)
[299294.578272] wlp58s0: authenticated
[299294.579344] wlp58s0: associate with 18:a6:f7:32:37:ab (try 1/3)
[299294.583557] wlp58s0: RX AssocResp from 18:a6:f7:32:37:ab (capab=0x431 status=0 aid=2)
[299294.588342] wlp58s0: associated
[299294.608659] IPv6: ADDRCONF(NETDEV_CHANGE): wlp58s0: link becomes ready

ifconfig then says:

wlp58s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.2.110  netmask 255.255.255.0  broadcast 192.168.2.255
        inet6 2a01:cb08:897e:7a00:e6b3:18ff:fe2f:318b  prefixlen 64  scopeid 0x0<global>
        inet6 fe80::e6b3:18ff:fe2f:318b  prefixlen 64  scopeid 0x20<link>
        ether e4:b3:18:2f:31:8b  txqueuelen 1000  (Ethernet)
        RX packets 7080996  bytes 9820109755 (9.1 GiB)
        RX errors 0  dropped 1  overruns 0  frame 0
        TX packets 2326384  bytes 274722217 (261.9 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

If I point my browser to http://192.168.2.1/ I get the login mask for the router.

But I cannot get any internet connection to the outside world:

ping 151.101.1.69
PING 151.101.1.69 (151.101.1.69) 56(84) bytes of data.
From 192.168.2.1 icmp_seq=1 Destination Net Unreachable
From 192.168.2.1 icmp_seq=2 Destination Net Unreachable

This has happened to me on multiple "similar" computers (always Debian Testing without a DE) over the years and is happening less and less frequently but right now I'm in such a network.

The output of route (as suggested in a comment) is:

$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.2.1     0.0.0.0         UG    0      0        0 wlp58s0
169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 wlp58s0
192.168.2.0     0.0.0.0         255.255.255.0   U     0      0        0 wlp58s0

My latest try has been to try to use opendns by adding to the

    wpa-ssid XXXXXXXXX
    wpa-psk YYYYYYYYYY
    dns-nameservers 208.67.222.222 208.67.220.220

But It did not work.

What can I try to get a working internet connection?


Update: If I stop the networking and use the tethering from an Android tablet, then the laptop can use the connection the tablet has built with the same network.


As requested, here the tcpdump output for three packets sent to 192.168.2.1 and then to 1.1.1.1:

tcpdump -n -i wlp58s0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on wlp58s0, link-type EN10MB (Ethernet), capture size 262144 bytes
13:48:59.227404 IP 192.168.2.1.42052 > 255.255.255.255.7437: UDP, length 173
13:49:01.538860 IP 192.168.2.111 > 192.168.2.1: ICMP echo request, id 17222, seq 1, length 64
13:49:01.540630 IP 192.168.2.1 > 192.168.2.111: ICMP echo reply, id 17222, seq 1, length 64
13:49:02.094846 IP 192.168.2.1.42052 > 255.255.255.255.7437: UDP, length 173
13:49:02.541021 IP 192.168.2.111 > 192.168.2.1: ICMP echo request, id 17222, seq 2, length 64
13:49:02.542778 IP 192.168.2.1 > 192.168.2.111: ICMP echo reply, id 17222, seq 2, length 64
13:49:03.543168 IP 192.168.2.111 > 192.168.2.1: ICMP echo request, id 17222, seq 3, length 64
13:49:03.544845 IP 192.168.2.1 > 192.168.2.111: ICMP echo reply, id 17222, seq 3, length 64
13:49:05.167181 IP 192.168.2.1.42052 > 255.255.255.255.7437: UDP, length 173
13:49:05.357735 IP 192.168.2.111 > 1.1.1.1: ICMP echo request, id 17234, seq 1, length 64
13:49:05.359445 IP 192.168.2.1 > 192.168.2.111: ICMP net 1.1.1.1 unreachable, length 92
13:49:06.359858 IP 192.168.2.111 > 1.1.1.1: ICMP echo request, id 17234, seq 2, length 64
13:49:06.361538 IP 192.168.2.1 > 192.168.2.111: ICMP net 1.1.1.1 unreachable, length 92
13:49:06.600727 ARP, Request who-has 192.168.2.111 tell 192.168.2.1, length 28
13:49:06.600779 ARP, Reply 192.168.2.111 is-at e4:b3:18:2f:31:8b, length 28
13:49:07.361967 IP 192.168.2.111 > 1.1.1.1: ICMP echo request, id 17234, seq 3, length 64
13:49:07.363836 IP 192.168.2.1 > 192.168.2.111: ICMP net 1.1.1.1 unreachable, length 92
13:49:08.239176 IP 192.168.2.1.42052 > 255.255.255.255.7437: UDP, length 173
13:49:08.449494 IP 192.168.1.1.5353 > 224.0.0.251.5353: 0 [5a] PTR (QM)? _services._dns-sd._udp.local. (168)
^C
19 packets captured
19 packets received by filter
0 packets dropped by kernel
  • Can you please add the output of route -n or ip route to your question. – Fanatique May 10 at 8:44
  • Yes, I've added it now! – a.l.e May 10 at 8:53
  • Considering that all routes are properly configured and you do have connection to your router.. the problem should be in the router's configuration. Can you actually try pinging 1.1.1.1 just to see that the problem is from the router and not from the IP address you're pinging? – Fanatique May 10 at 9:04
  • 1.1.1.1 is not reachable when i'm using the "affected" router. – a.l.e May 10 at 9:13
  • (1) The router and/or ISP may decide to block the ping (ICMP) using a firewall. Try e.g. echo 'GET /' | nc www.google.de 80 or telnet www.google.de:80 etc. to check if TCP works. Use numeric IPs if DNS is not working. (2) There are more comfortable ways to manager Wifi connections from the commandline, for example wpa_supplicant with a configuration file for roaming connections (see documentation), or other programs like Network Manager. – dirkt May 10 at 9:20
1

As you have connection to your router, your routes are properly configured, and you have no internet connection to outside of the LAN - then the problem should lie within the router and its internet connection/configuration, not yours. It is also not a problem with DNS, as you're pinging simple IP addresses.

What can I try to get a working internet connection?

If you have access to the router's control panel, try checking its configuration to see if anything is wrong (gateway, IP address, mode of operation, etc.). You can also ask another question about the problem with the router.

If not, I doubt you'd be able to get a working connection in any way, unless whoever manages that router fixes it.

  • Thank you for your reply. All other devices can get a working connect, My Android tablet included. I just discovered that I've made an error earlier this morning and that I now can use the the same Wifi through USB tethering. It's not my router, but I fear that I won't find anything useful by clicking around... Finally, thanks for hinting that it's not a DNS issue. – a.l.e May 10 at 9:44

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